Paper-based material with reversible multi-color change and preparation and application thereof

Abstract

The application discloses a paper-based material with reversible multi-color change and a preparation and application thereof, and a method which comprises the following steps: dissolving a transition metal heteropoly acid salt, a plasticizer, an electron-donating polymer and silver nitrate in a solvent to prepare a mixed solution; uniformly coating the mixed solution on a paper surface, and obtaining the paper-based material with reversible multi-color change after drying. The raw materials are directly dissolved in the solvent, and are uniformly coated on the paper base through a simple coating method, so that the preparation process is efficient, energy-saving and easy to realize large-scale preparation. The paper-based material prepared by the application can rapidly change color under ultraviolet light irradiation, and different colors can be realized according to different amounts of silver ions, so that personalized selection is enriched. After the paper-based material prepared by the application changes color, the color information can be kept stable for a long time at room temperature, and if necessary, the color can be faded within 20 minutes by means of hydrogen peroxide, so that the fading time is controllable.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, specifically relating to a paper-based material with reversible multi-color changes and its preparation and application. Background Technology

[0002] The paper industry is a vital sector closely linked to national economic and social development. Paper products are now widely used in all aspects of people's lives, playing a crucial role in promoting both material and spiritual civilization. Surveys show that my country's paper consumption exceeds 110 million tons, with over 30% used for printing and other printing-related purposes. Globally, over 90% of printing paper is used for short-term reading, and approximately 40% of printed or photocopied paper is sent to the wastebasket after only one reading. This massive paper waste will seriously impact our sustainable development strategy.

[0003] Photochromic materials are materials whose molecular structure changes and thus their color changes under the influence of light of a certain wavelength and intensity. This reversible property makes them potentially applicable in the field of rewritable paper. Molybdenum, tungsten, and other transition metal heteropolyacids commonly used to prepare these photoresponsive materials generate heteropolyblue upon exposure to ultraviolet light, resulting in a color change. However, due to the metastable state of heteropolyblue, this color information is only temporarily retained, and the single blue color change limits its widespread application. Furthermore, while silver ion-based photochromic materials can achieve different color changes within a certain range, most of them are visible light responsive, and the light-shielding treatment during use greatly hinders their application. Summary of the Invention

[0004] In view of the shortcomings and deficiencies of the existing technology, the primary objective of this invention is to provide a method for preparing paper-based materials with reversible multi-color changes.

[0005] Another object of the present invention is to provide a paper-based material with reversible multi-color changes prepared by the above method.

[0006] Another object of the present invention is to provide applications of the above-mentioned paper-based material having reversible multi-color changes.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a paper-based material with reversible multi-color changes includes the following steps:

[0009] (1) A mixed solution was prepared by dissolving transition metal heteropolyacid salts, plasticizers, electron-donating polymers and silver nitrate in a solvent;

[0010] (2) The mixed solution is evenly coated on the surface of paper and dried to obtain a paper-based material with reversible multi-color changes.

[0011] Preferably, the transition metal heteropolyacid salt is at least one of phosphomolybdic acid, phosphotungstic acid, or ammonium metatungstate, more preferably ammonium metatungstate.

[0012] Preferably, the plasticizer is at least one of ethylene glycol, glycerin, or polyethylene glycol, more preferably ethylene glycol.

[0013] Preferably, the electron-donating polymer is at least one of polyvinylpyrrolidone or gelatin, more preferably polyvinylpyrrolidone.

[0014] Preferably, the solvent is at least one of isopropanol, ethanol, or water, more preferably water.

[0015] Preferably, in step (1), the mass ratio of transition metal heteropolyacid salt, plasticizer, electron-donating polymer, silver nitrate, and solvent is (10–50):(0–5):(1–5):(0–30)×10. -5 (10-60), more preferably 30:2.2:3:5×10 -5 :30.

[0016] Preferably, the coating thickness in step (2) is 50 to 300 μm, more preferably 80 μm.

[0017] A paper-based material with reversible multi-color changes is prepared by the above-described preparation method.

[0018] The above-mentioned applications of paper-based materials with reversible multi-color changes.

[0019] The mechanism of this invention is as follows:

[0020] 1. Mechanism of heteropolyblue formation: Under ultraviolet irradiation, photogenerated electrons transition from terminal oxygen to the dd orbitals of the metal. Protons from the electron donor (organic polymer) are transferred to the common-side oxygen atoms of its oxygen cluster octahedral lattice, forming charge-transfer complexes. During this charge transfer process, the high-valence transition metal is reduced, producing heteropolyblue and achieving the color change.

[0021] 2. Mechanism of silver ions being reduced to nano-silver and producing multi-color: During the coloring process, the reducing heteropoly blue reduces some silver ions to nano-silver particles; in addition, photogenerated electrons with strong reducing properties can also directly reduce silver ions to nano-silver particles, and the different sizes and distributions of nano-silver particles will cause the material to present different colors.

[0022] 3. Color mixing mechanism between the blue of heteropoly blue and the color of nano silver: The different sizes and distributions of nano silver particles will cause the material to present different colors. When these colors are mixed with the blue of heteropoly blue, they can present corresponding mixed colors. This color mixing mechanism follows the subtractive color mixing method of pigments.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) The present invention directly dissolves the raw materials in a solvent and coats them evenly onto the paper base through a simple coating method. The preparation process is efficient, energy-saving, and easy to achieve large-scale preparation.

[0025] (2) The paper-based material prepared by the present invention changes color rapidly under ultraviolet light. Depending on the amount of silver ions added, different colors can be achieved, enriching personalized choices.

[0026] (3) After the paper-based material prepared by the present invention changes color, the color information can remain stable for a long time at room temperature. If necessary, hydrogen peroxide can be used to make it fade quickly within 20 minutes, so that the fading time can be controlled. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 Images showing the color changes of the paper-based material samples prepared in Examples 1-4 under different ultraviolet light irradiation durations.

[0029] Figure 2 This is a schematic diagram and optical photograph of the paper-based material sample prepared in Example 2 undergoing rapid fading in a hydrogen peroxide environment.

[0030] Figure 3 AFM images of the paper-based material samples prepared in Examples 2 and 4 after coloring.

[0031] Figure 4 The diffuse reflectance spectra of the paper-based material sample prepared in Example 5 under different ultraviolet light irradiation durations are shown.

[0032] Figure 5 The diffuse reflectance spectrum and optical photograph of the paper-based material sample prepared in Example 6 after being placed at room temperature for 99 days.

[0033] Figure 6A schematic diagram of the paper-based material sample prepared in Example 7 being photoprinted, and a photograph of the photoprinted sample.

[0034] Figure 7 This is a surface morphology image of the paper-based material sample prepared in Example 8. Detailed Implementation

[0035] The following embodiments are provided to further illustrate the present invention, but are not intended to limit the invention. It should be noted that the embodiments are only for further illustration and should not be construed as limiting the scope of protection of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make some non-essential improvements and adjustments based on the above description of the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0036] Unless otherwise specified, all reagents and instruments used in this invention are commercially available products. For process parameters not specifically stated, conventional techniques can be used as a reference.

[0037] Example 1

[0038] (1) Dissolve 10g ammonium metatungstate, 2.2g ethylene glycol, 1g polyvinylpyrrolidone, and 0mg silver nitrate in 10g water to prepare a mixed solution;

[0039] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 80 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0040] Images showing the color changes of the paper-based material sample prepared in this embodiment under different ultraviolet light irradiation durations are shown below. Figure 1 As shown.

[0041] Example 2

[0042] (1) Dissolve 30g ammonium metatungstate, 2.2g ethylene glycol, 3g polyvinylpyrrolidone, and 0.05mg silver nitrate in 30g water to prepare a mixed solution;

[0043] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 80 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0044] Images showing the color changes of the paper-based material sample prepared in this embodiment under different ultraviolet light irradiation durations are shown below. Figure 1 As shown.

[0045] The schematic diagram and optical photograph of the paper-based material sample prepared in this embodiment undergoing rapid fading in a hydrogen peroxide environment are shown below. Figure 2 As shown, Figure 2 This indicates that hydrogen peroxide can be used to achieve rapid fading within 20 minutes, making the fading time controllable.

[0046] The AFM image of the paper-based material sample prepared in this embodiment after coloring is shown below. Figure 3 As shown.

[0047] Example 3

[0048] (1) Dissolve 30g ammonium metatungstate, 2.2g ethylene glycol, 3g polyvinylpyrrolidone, and 0.1mg silver nitrate in 30g water to prepare a mixed solution;

[0049] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 80 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0050] Images showing the color changes of the paper-based material sample prepared in this embodiment under different ultraviolet light irradiation durations are shown below. Figure 1 As shown.

[0051] Example 4

[0052] (1) Dissolve 30g ammonium metatungstate, 2.2g ethylene glycol, 3g polyvinylpyrrolidone, and 0.15mg silver nitrate in 30g water to prepare a mixed solution;

[0053] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 80 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0054] Images showing the color changes of the paper-based material sample prepared in this embodiment under different ultraviolet light irradiation durations are shown below. Figure 1 As shown, from Figure 1 The test results of the samples in Examples 1 to 4 show that the paper-based material samples prepared with different amounts of silver ions exhibit different colors, and the color intensity gradually deepens with the increase of irradiation time.

[0055] The AFM image of the paper-based material sample prepared in this embodiment after coloring is shown below. Figure 3 As shown, from Figure 3 The test results of samples in Examples 2 and 4 show that the paper-based material samples prepared with different amounts of silver ions have different sizes and distributions of silver nanoparticles after color change, and different sizes and distributions will cause the material to present different colors.

[0056] Example 5

[0057] (1) Dissolve 50g ammonium metatungstate, 2.2g ethylene glycol, 5g polyvinylpyrrolidone, and 0.08mg silver nitrate in 50g water to prepare a mixed solution;

[0058] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 60 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0059] The surface diffuse reflectance spectra of the paper-based material samples prepared in this embodiment under different ultraviolet light irradiation durations are shown below. Figure 4 As shown in the figure, the reflectivity gradually decreases with the extension of irradiation time, indicating that the amount of light reflected from the surface gradually decreases and the color intensity of the sample surface gradually deepens.

[0060] Example 6

[0061] (1) Dissolve 50g ammonium metatungstate, 5g ethylene glycol, 5g polyvinylpyrrolidone, and 0.3mg silver nitrate in 60g water to prepare a mixed solution;

[0062] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 50 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0063] The diffuse reflectance spectrum and optical photograph of the paper-based material sample prepared in this embodiment after being placed at room temperature for 99 days are shown below. Figure 5 As shown, the color information of the sample remains stable even after a long period of storage.

[0064] Example 7

[0065] (1) Dissolve 30g ammonium metatungstate, 3g ethylene glycol, 4g polyvinylpyrrolidone, and 0.1mg silver nitrate in 30g water to prepare a mixed solution;

[0066] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 300 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0067] This embodiment presents a schematic diagram of the paper-based material sample being photoprinted, and a photograph of the sample after photoprinting is completed. Figure 6 As shown, this indicates that the sample has the potential to accurately transmit information.

[0068] Example 8

[0069] (1) Dissolve 30g ammonium metatungstate, 0g ethylene glycol, 3g polyvinylpyrrolidone, and 0.01mg silver nitrate in 30g water to prepare a mixed solution;

[0070] (2) The mixed solution from step (1) is uniformly coated on the surface of paper with a coating thickness of 80 μm. After the paper dries, a paper-based material with reversible multi-color changes is obtained.

[0071] The surface morphology of the paper-based material sample prepared in this embodiment is as follows: Figure 7 As shown, the coating forms a smooth surface, but some microcracks appear during the drying process, which will increase the specific surface area to a certain extent and further improve its photoresponse rate.

[0072] The above description, in conjunction with specific embodiments, provides a further detailed explanation of this application and should not be construed as limiting the specific implementation of this application to these descriptions. Those skilled in the art to which this application pertains can make several simple deductions or substitutions without departing from the concept of this application.

Claims

1. A method of making a paper-based material having reversible multi-color change, characterized by, The method comprises the following steps: (1) dissolving transition metal heteropoly acid salt, plasticizer, electron donor polymer and silver nitrate in a solvent to prepare a mixed solution; (2) uniformly coating the mixed solution on the surface of paper, and drying to obtain the paper-based material with reversible multi-color change; The mass ratio of the transition metal heteropoly acid salt, the plasticizer, the electron-donating polymer, silver nitrate and the solvent in step (1) is 50:5:5:30x10 -5 :

60.

2. The method of claim 1, wherein the paper-based material having reversible multi-color change is prepared by the steps of: The transition metal heteropoly acid salt is at least one of phosphomolybdic acid, phosphotungstic acid or ammonium metatungstate.

3. The method of claim 1, wherein the paper-based material having reversible multi-color change is prepared by the steps of: The plasticizer is at least one of ethylene glycol, glycerol or polyethylene glycol.

4. The method of claim 1, wherein the paper-based material having reversible multi-color change is prepared by the steps of: The electron donor polymer is at least one of polyvinylpyrrolidone or gelatin.

5. The method of claim 1, wherein the paper-based material having reversible multi-color change is prepared by the steps of: The solvent is at least one of isopropyl alcohol, ethanol or water.

6. The method of claim 1, wherein the paper-based material having reversible multi-color change is prepared by the steps of: The thickness of the coating in step (2) is 50-300 μm.

7. The paper-based material with reversible multi-color change prepared by the method for preparing the paper-based material with reversible multi-color change according to any one of claims 1-6.

8. The paper-based material with reversible multi-color change according to claim 7.

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